We have known for some time that the full iPhone 12 lineup, from the 5.4-inch iPhone 12 mini to the 6.7-inch iPhone 12 Pro Max, will support 5G. But now it appears that the iPhone 12 will have a 5G advantage over all the best Android phones.

This is according to Kang on Chinese social networking site Weibo, who says Apple is preparing something called "Smart Data Mode" for the iPhone 12.

"My understanding is that 4G/5G will be allocated based on application bandwidth," Kang wrote.

In other words, it appears that the iPhone 12 will only use ultra-fast 5G connections when absolutely necessary, and use 4G in areas where time is not critical, such as apps running in the background.

Those with unlimited data may feel a bit shortchanged, but it's also wise for them: 5G consumes more power than LTE. Therefore, the iPhone 12's Smart Data mode should give Apple a power efficiency advantage and longer battery life compared to newer Android rivals like the Galaxy S20 FE, Pixel 5, and OnePlus 8T.

Kang also suggests that all iPhone 12 models in the US will support mmWave in addition to sub-6GHz. While sub-6GHz 5G phones remain much faster than 4G LTE phones, they cannot download an entire Netflix TV series in seconds, as mmWave phones potentially can.

This iPhone 12 leak is in contrast to other leaks we heard about back in May, when leaker Jon Prosser tweeted that he heard mmWave was reserved for the more expensive iPhone 12 Pro and Pro Max models.

We'll know for sure in just a few days; the iPhone 12 event is set for Tuesday (1 p.m. EDT/10 a.m. PDT). Judging from leaked iPad Air benchmarks, all four devices will use the A14 Bionic chip.

The lower-priced 5.4-inch iPhone 12 mini and 6.1-inch iPhone 12 will feature dual cameras, while the 6.1-inch Pro and 6.7-inch Pro Max will have three lenses and LiDAR sensors. There are conflicting reports as to whether the latter two will be upgraded to 120Hz screens, but at this point it seems likely that this is a feature of the iPhone 13.